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agomes
Staff
Staff
March 25, 2025

Technical Tip: BGP Redundancy with route map

  • March 25, 2025
  • 0 replies
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Description

This article describes setting up BGP Redundancy using route-map.

Scope FortiGate 7.x and earlier.
Solution

Topology:

 

2025-03-24 10_02_52-Excalidraw and 11 more pages - Personal - Microsoft​ Edge.png

 

  1. Create the respective interfaces in the Firewalls:

FIREWALL-DC config system interface     edit "port1"         set vdom "root"         set ip 10.0.1.1 255.255.255.0         set allowaccess ping         set type physical         set alias "Link-01"         set snmp-index 1     next     edit "port2"         set vdom "root"         set ip 10.0.2.1 255.255.255.0         set allowaccess ping         set type physical         set alias "Link-02"         set snmp-index 2     next     edit "Loopback01"         set vdom "root"         set ip 172.21.254.1 255.255.255.0         set allowaccess ping         set type loopback         set role lan         set snmp-index 13     next  

 

Firewall-Branch1  config system interface     edit "port1"         set vdom "root"         set ip 10.0.1.2 255.255.255.0         set allowaccess ping         set type physical         set alias "Link-01"         set snmp-index 1     next     edit "port2"         set vdom "root"         set ip 10.0.2.2 255.255.255.0         set allowaccess ping         set type physical         set alias "Link-02"         set snmp-index 2     next     edit "Loopback01"         set vdom "root"         set ip 192.168.1.1 255.255.255.0         set allowaccess ping         set type loopback         set role lan         set snmp-index 13     next  

 

Firewall-Branch2  edit "port1"         set vdom "root"         set ip 10.0.1.3 255.255.255.0         set allowaccess ping         set type physical         set alias "Link-01"         set snmp-index 1     next     edit "port2"         set vdom "root"         set ip 10.0.2.3 255.255.255.0         set allowaccess ping         set type physical         set alias "Link-02"         set snmp-index 2     edit "Loopback01"         set vdom "root"         set ip 192.168.2.1 255.255.255.0         set allowaccess ping         set type loopback         set role lan         set snmp-index 13     next  

 

  1. Configure the BGP peers between the links.

Firewall-DC  config router bgp     set as 65000     set router-id 172.21.254.1     config neighbor         edit "10.0.1.2"             set interface "port1"             set remote-as 65001         next         edit "10.0.1.3"             set interface "port1"             set remote-as 65002         next         edit "10.0.2.2"             set interface "port2"             set remote-as 65001         next         edit "10.0.2.3"             set interface "port2"             set remote-as 65002         next     end 

 

Firewall-Branch1  config router bgp     set as 65001     set router-id 192.168.1.1     config neighbor         edit "10.0.1.1"             set remote-as 65000         next         edit "10.0.2.1"             set remote-as 65000         next     end 

 

Firewall-Branch2  config router bgp     set as 65002     set router-id 192.168.2.1     config neighbor         edit "10.0.1.1"             set remote-as 65000         next         edit "10.0.2.1"             set remote-as 65000         next     end 

 

  1. Configure the network to be advertised.

Firewall-DC  config router bgp     set as 65000     set router-id 172.21.254.1     config network         edit 1             set prefix 172.21.254.0 255.255.255.0         next     end  

 

Firewall-Branch1 config router bgp     set as 65001     set router-id 192.168.1.1      config network         edit 1             set prefix 192.168.1.0 255.255.255.0         next     end  

 

Firewall-Branch2 config router bgp     set as 65002     set router-id 192.168.2.1      config network         edit 1             set prefix 192.168.2.0 255.255.255.0         next     end  

 

  1. Configure the route-map to set local preference to link1 as preferred to link2.

 

Firewall-DC  config router route-map     edit "map-in-link01"         config rule             edit 1                 set match-ip-address "prefix-in"                 set set-local-preference 200             next         end     next     edit "map-in-link02"         config rule             edit 1                 set match-ip-address "prefix-in"                 set set-local-preference 100             next         end     next end 

 

  1. Adjust the BGP config to use the route-map.

 

Firewall_DC  config router bgp     set as 65000     set router-id 172.21.254.1     config neighbor         edit "10.0.1.2"             set interface "port1"             set remote-as 65001             set route-map-in "map-in-link01" <----------------         next         edit "10.0.1.3"             set interface "port1"             set remote-as 65002             set route-map-in "map-in-link01" <----------------         next         edit "10.0.2.2"             set interface "port2"             set remote-as 65001             set route-map-in "map-in-link02" <----------------         next         edit "10.0.2.3"             set interface "port2"             set remote-as 65002             set route-map-in "map-in-link02" <----------------         next     end 

 

  1. Check the routing table.

 

get router info bgp network VRF 0 BGP table version is 3, local router ID is 172.21.254.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,               S Stale Origin codes: i - IGP, e - EGP, ? - incomplete     Network          Next Hop            Metric     LocPrf Weight RouteTag Path *> 172.21.254.0/24  0.0.0.0                       100  32768        0 i <-/1> *> 192.168.1.0      10.0.1.2        0             200      0        0 65001 i <-/1>  *                   10.0.2.2        0             100      0        0 65001 i <-/->  *  192.168.2.0      10.0.2.3        0             100      0        0 65002 i <-/-> *>                  10.0.1.3        0             200      0        0 65002 i <-/1>  Total number of prefixes 3  get router info routing-table bgp Routing table for VRF=0 B       192.168.1.0/24 [20/0] via 10.0.1.2 (recursive is directly connected, port1), 1d19h31m, [1/0] B       192.168.2.0/24 [20/0] via 10.0.1.3 (recursive is directly connected, port1), 1d19h31m, [1/0]

 

  1. Note how the local preference on link2 (10.0.2.0/24) has the lower preference (100) as configured before, and the routes installed into the routing table are using the link01.